1. Technical Field
This disclosure relates to a recording paper conveying apparatus, an inkjet recording apparatus, and a method for controlling the conveyance of recording paper, and more particularly, to a recording paper conveying apparatus, an inkjet recording apparatus, and a method for controlling the conveyance of recording paper by a recording paper conveying apparatus with high precision.
2. Description of the Related Art
Recently, in the field of inkjet recording technology, the types of ink used for recording are shifting from dye type inks to pigment type inks for improving light resistance and aging resistance (resistance against deterioration in association with time). In addition, the viscosity of the ink is becoming higher. Although the increase in the viscosity of the ink has reduced creation of bleeding on the recording paper considerably, inaccurate disposition of ink droplets where ink droplets deviate from a target contact area (e.g. white stripes, black stripes, banding) is more visible. Since the disposition of ink droplets largely relies on the precision of the stop position during conveyance of a recording paper in a sub-scanning direction, it is desired to increase the precision in conveying the recording paper.
Conventionally, a grinding conveyor roller or a conveyor belt is employed in a sub-scan recording paper conveying mechanism used for inkjet recording. In controlling the amount of conveyance with the conveying mechanism, a code wheel is provided on an axle of a conveying roller for allowing an encoder sensor to read and control the conveyance according to a value obtained from the code wheel. For example, Japanese Laid-Open Patent Application No. 2002-248822 shows a configuration where a conveying roller and a discharge roller are situated at an upstream side and a downstream side of a platen for conveying a recording paper in a sub-scanning direction. This configuration has a code wheel provided on an axle of the conveying roller for allowing an encoder sensor to read and control the conveyance according to a value obtained from the code wheel.
However, the conventional recording paper conveying mechanism using the code wheel and the sensor for controlling the conveyance of the recording paper has difficulty in achieving stop position control with satisfactory precision due to overlapping error among its components (e.g. pulley, conveying roller, etc.).